MySQL & PHP decimal precision wrong

Question

24151.40 - 31891.10 = -7739.699999999997

I grab these two numbers from a MySQL table with the type as decimal(14,2) 24151.40 31891.10 It is saved exactly as stated abov

Answer 1

PHP doesn't have a decimal type like MySQL does, it uses floats; and floats are notorious for being inaccurate.

To cure this, look into number_format, e.g.:

echo number_format(24151.40 - 31891.10, 2, '.', '');

For more accurate number manipulation, you could also look at the math extensions of PHP:

http://www.php.net/manual/en/refs.math.php